6a9056a926
implement most of the proc provider. Adds proc:::create, exec, exec_success, exec_faillure, signal_send, signal_discard, signal_handle, lwp_create, lwp_start, lwp_exit.
545 lines
15 KiB
C
545 lines
15 KiB
C
/* $NetBSD: kern_fork.c,v 1.176 2010/03/01 21:10:16 darran Exp $ */
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/*-
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* Copyright (c) 1999, 2001, 2004, 2006, 2007, 2008 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
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* NASA Ames Research Center, by Charles M. Hannum, and by Andrew Doran.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* Copyright (c) 1982, 1986, 1989, 1991, 1993
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* The Regents of the University of California. All rights reserved.
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* (c) UNIX System Laboratories, Inc.
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* All or some portions of this file are derived from material licensed
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* to the University of California by American Telephone and Telegraph
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* Co. or Unix System Laboratories, Inc. and are reproduced herein with
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* the permission of UNIX System Laboratories, Inc.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)kern_fork.c 8.8 (Berkeley) 2/14/95
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: kern_fork.c,v 1.176 2010/03/01 21:10:16 darran Exp $");
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#include "opt_ktrace.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/filedesc.h>
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#include <sys/kernel.h>
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#include <sys/pool.h>
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#include <sys/mount.h>
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#include <sys/proc.h>
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#include <sys/ras.h>
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#include <sys/resourcevar.h>
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#include <sys/vnode.h>
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#include <sys/file.h>
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#include <sys/acct.h>
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#include <sys/ktrace.h>
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#include <sys/vmmeter.h>
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#include <sys/sched.h>
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#include <sys/signalvar.h>
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#include <sys/kauth.h>
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#include <sys/atomic.h>
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#include <sys/syscallargs.h>
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#include <sys/uidinfo.h>
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#include <sys/sdt.h>
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#include <uvm/uvm_extern.h>
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/*
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* DTrace SDT provider definitions
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*/
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SDT_PROBE_DEFINE(proc,,,create,
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"struct proc *", NULL, /* new process */
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"struct proc *", NULL, /* parent process */
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"int", NULL, /* flags */
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NULL, NULL, NULL, NULL);
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u_int nprocs = 1; /* process 0 */
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/*
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* Number of ticks to sleep if fork() would fail due to process hitting
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* limits. Exported in miliseconds to userland via sysctl.
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*/
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int forkfsleep = 0;
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/*ARGSUSED*/
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int
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sys_fork(struct lwp *l, const void *v, register_t *retval)
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{
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return (fork1(l, 0, SIGCHLD, NULL, 0, NULL, NULL, retval, NULL));
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}
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/*
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* vfork(2) system call compatible with 4.4BSD (i.e. BSD with Mach VM).
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* Address space is not shared, but parent is blocked until child exit.
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*/
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/*ARGSUSED*/
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int
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sys_vfork(struct lwp *l, const void *v, register_t *retval)
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{
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return (fork1(l, FORK_PPWAIT, SIGCHLD, NULL, 0, NULL, NULL,
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retval, NULL));
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}
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/*
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* New vfork(2) system call for NetBSD, which implements original 3BSD vfork(2)
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* semantics. Address space is shared, and parent is blocked until child exit.
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*/
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/*ARGSUSED*/
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int
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sys___vfork14(struct lwp *l, const void *v, register_t *retval)
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{
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return (fork1(l, FORK_PPWAIT|FORK_SHAREVM, SIGCHLD, NULL, 0,
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NULL, NULL, retval, NULL));
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}
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/*
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* Linux-compatible __clone(2) system call.
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*/
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int
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sys___clone(struct lwp *l, const struct sys___clone_args *uap, register_t *retval)
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{
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/* {
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syscallarg(int) flags;
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syscallarg(void *) stack;
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} */
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int flags, sig;
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/*
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* We don't support the CLONE_PID or CLONE_PTRACE flags.
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*/
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if (SCARG(uap, flags) & (CLONE_PID|CLONE_PTRACE))
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return (EINVAL);
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/*
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* Linux enforces CLONE_VM with CLONE_SIGHAND, do same.
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*/
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if (SCARG(uap, flags) & CLONE_SIGHAND
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&& (SCARG(uap, flags) & CLONE_VM) == 0)
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return (EINVAL);
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flags = 0;
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if (SCARG(uap, flags) & CLONE_VM)
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flags |= FORK_SHAREVM;
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if (SCARG(uap, flags) & CLONE_FS)
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flags |= FORK_SHARECWD;
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if (SCARG(uap, flags) & CLONE_FILES)
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flags |= FORK_SHAREFILES;
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if (SCARG(uap, flags) & CLONE_SIGHAND)
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flags |= FORK_SHARESIGS;
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if (SCARG(uap, flags) & CLONE_VFORK)
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flags |= FORK_PPWAIT;
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sig = SCARG(uap, flags) & CLONE_CSIGNAL;
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if (sig < 0 || sig >= _NSIG)
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return (EINVAL);
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/*
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* Note that the Linux API does not provide a portable way of
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* specifying the stack area; the caller must know if the stack
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* grows up or down. So, we pass a stack size of 0, so that the
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* code that makes this adjustment is a noop.
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*/
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return (fork1(l, flags, sig, SCARG(uap, stack), 0,
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NULL, NULL, retval, NULL));
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}
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/* print the 'table full' message once per 10 seconds */
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struct timeval fork_tfmrate = { 10, 0 };
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/*
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* General fork call. Note that another LWP in the process may call exec()
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* or exit() while we are forking. It's safe to continue here, because
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* neither operation will complete until all LWPs have exited the process.
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*/
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int
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fork1(struct lwp *l1, int flags, int exitsig, void *stack, size_t stacksize,
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void (*func)(void *), void *arg, register_t *retval,
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struct proc **rnewprocp)
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{
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struct proc *p1, *p2, *parent;
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struct plimit *p1_lim;
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uid_t uid;
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struct lwp *l2;
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int count;
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vaddr_t uaddr;
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int tmp;
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int tnprocs;
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int error = 0;
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p1 = l1->l_proc;
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uid = kauth_cred_getuid(l1->l_cred);
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tnprocs = atomic_inc_uint_nv(&nprocs);
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/*
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* Although process entries are dynamically created, we still keep
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* a global limit on the maximum number we will create.
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*/
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if (__predict_false(tnprocs >= maxproc))
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error = -1;
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else
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error = kauth_authorize_process(l1->l_cred,
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KAUTH_PROCESS_FORK, p1, KAUTH_ARG(tnprocs), NULL, NULL);
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if (error) {
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static struct timeval lasttfm;
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atomic_dec_uint(&nprocs);
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if (ratecheck(&lasttfm, &fork_tfmrate))
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tablefull("proc", "increase kern.maxproc or NPROC");
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if (forkfsleep)
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kpause("forkmx", false, forkfsleep, NULL);
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return (EAGAIN);
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}
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/*
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* Enforce limits.
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*/
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count = chgproccnt(uid, 1);
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if (kauth_authorize_generic(l1->l_cred, KAUTH_GENERIC_ISSUSER, NULL) !=
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0 && __predict_false(count > p1->p_rlimit[RLIMIT_NPROC].rlim_cur)) {
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(void)chgproccnt(uid, -1);
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atomic_dec_uint(&nprocs);
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if (forkfsleep)
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kpause("forkulim", false, forkfsleep, NULL);
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return (EAGAIN);
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}
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/*
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* Allocate virtual address space for the U-area now, while it
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* is still easy to abort the fork operation if we're out of
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* kernel virtual address space.
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*/
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uaddr = uvm_uarea_alloc();
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if (__predict_false(uaddr == 0)) {
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(void)chgproccnt(uid, -1);
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atomic_dec_uint(&nprocs);
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return (ENOMEM);
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}
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/*
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* We are now committed to the fork. From here on, we may
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* block on resources, but resource allocation may NOT fail.
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*/
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/* Allocate new proc. */
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p2 = proc_alloc();
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/*
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* Make a proc table entry for the new process.
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* Start by zeroing the section of proc that is zero-initialized,
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* then copy the section that is copied directly from the parent.
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*/
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memset(&p2->p_startzero, 0,
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(unsigned) ((char *)&p2->p_endzero - (char *)&p2->p_startzero));
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memcpy(&p2->p_startcopy, &p1->p_startcopy,
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(unsigned) ((char *)&p2->p_endcopy - (char *)&p2->p_startcopy));
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CIRCLEQ_INIT(&p2->p_sigpend.sp_info);
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LIST_INIT(&p2->p_lwps);
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LIST_INIT(&p2->p_sigwaiters);
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/*
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* Duplicate sub-structures as needed.
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* Increase reference counts on shared objects.
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* Inherit flags we want to keep. The flags related to SIGCHLD
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* handling are important in order to keep a consistent behaviour
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* for the child after the fork.
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*/
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p2->p_flag = p1->p_flag & (PK_SUGID | PK_NOCLDWAIT | PK_CLDSIGIGN);
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p2->p_emul = p1->p_emul;
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p2->p_execsw = p1->p_execsw;
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if (flags & FORK_SYSTEM) {
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/*
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* Mark it as a system process. Set P_NOCLDWAIT so that
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* children are reparented to init(8) when they exit.
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* init(8) can easily wait them out for us.
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*/
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p2->p_flag |= (PK_SYSTEM | PK_NOCLDWAIT);
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}
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mutex_init(&p2->p_stmutex, MUTEX_DEFAULT, IPL_HIGH);
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mutex_init(&p2->p_auxlock, MUTEX_DEFAULT, IPL_NONE);
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rw_init(&p2->p_reflock);
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cv_init(&p2->p_waitcv, "wait");
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cv_init(&p2->p_lwpcv, "lwpwait");
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/*
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* Share a lock between the processes if they are to share signal
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* state: we must synchronize access to it.
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*/
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if (flags & FORK_SHARESIGS) {
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p2->p_lock = p1->p_lock;
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mutex_obj_hold(p1->p_lock);
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} else
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p2->p_lock = mutex_obj_alloc(MUTEX_DEFAULT, IPL_NONE);
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kauth_proc_fork(p1, p2);
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p2->p_raslist = NULL;
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#if defined(__HAVE_RAS)
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ras_fork(p1, p2);
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#endif
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/* bump references to the text vnode (for procfs) */
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p2->p_textvp = p1->p_textvp;
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if (p2->p_textvp)
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vref(p2->p_textvp);
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if (flags & FORK_SHAREFILES)
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fd_share(p2);
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else if (flags & FORK_CLEANFILES)
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p2->p_fd = fd_init(NULL);
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else
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p2->p_fd = fd_copy();
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if (flags & FORK_SHARECWD)
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cwdshare(p2);
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else
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p2->p_cwdi = cwdinit();
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/*
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* p_limit (rlimit stuff) is usually copy-on-write, so we just need
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* to bump pl_refcnt.
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* However in some cases (see compat irix, and plausibly from clone)
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* the parent and child share limits - in which case nothing else
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* must have a copy of the limits (PL_SHAREMOD is set).
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*/
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if (__predict_false(flags & FORK_SHARELIMIT))
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lim_privatise(p1, 1);
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p1_lim = p1->p_limit;
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if (p1_lim->pl_flags & PL_WRITEABLE && !(flags & FORK_SHARELIMIT))
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p2->p_limit = lim_copy(p1_lim);
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else {
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lim_addref(p1_lim);
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p2->p_limit = p1_lim;
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}
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p2->p_lflag = ((flags & FORK_PPWAIT) ? PL_PPWAIT : 0);
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p2->p_sflag = 0;
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p2->p_slflag = 0;
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parent = (flags & FORK_NOWAIT) ? initproc : p1;
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p2->p_pptr = parent;
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p2->p_ppid = parent->p_pid;
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LIST_INIT(&p2->p_children);
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p2->p_aio = NULL;
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#ifdef KTRACE
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/*
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* Copy traceflag and tracefile if enabled.
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* If not inherited, these were zeroed above.
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*/
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if (p1->p_traceflag & KTRFAC_INHERIT) {
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mutex_enter(&ktrace_lock);
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p2->p_traceflag = p1->p_traceflag;
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if ((p2->p_tracep = p1->p_tracep) != NULL)
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ktradref(p2);
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mutex_exit(&ktrace_lock);
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}
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#endif
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/*
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* Create signal actions for the child process.
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*/
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p2->p_sigacts = sigactsinit(p1, flags & FORK_SHARESIGS);
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mutex_enter(p1->p_lock);
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p2->p_sflag |=
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(p1->p_sflag & (PS_STOPFORK | PS_STOPEXEC | PS_NOCLDSTOP));
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sched_proc_fork(p1, p2);
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mutex_exit(p1->p_lock);
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p2->p_stflag = p1->p_stflag;
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/*
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* p_stats.
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* Copy parts of p_stats, and zero out the rest.
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*/
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p2->p_stats = pstatscopy(p1->p_stats);
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/*
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* If emulation has process fork hook, call it now.
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*/
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if (p2->p_emul->e_proc_fork)
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(*p2->p_emul->e_proc_fork)(p2, p1, flags);
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/*
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* ...and finally, any other random fork hooks that subsystems
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* might have registered.
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*/
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doforkhooks(p2, p1);
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uvm_proc_fork(p1, p2, (flags & FORK_SHAREVM) ? true : false);
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SDT_PROBE(proc,,,create, p2, p1, flags, 0, 0);
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/*
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* Finish creating the child process.
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* It will return through a different path later.
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*/
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lwp_create(l1, p2, uaddr, (flags & FORK_PPWAIT) ? LWP_VFORK : 0,
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stack, stacksize, (func != NULL) ? func : child_return, arg, &l2,
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l1->l_class);
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/*
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* It's now safe for the scheduler and other processes to see the
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* child process.
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*/
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mutex_enter(proc_lock);
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if (p1->p_session->s_ttyvp != NULL && p1->p_lflag & PL_CONTROLT)
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p2->p_lflag |= PL_CONTROLT;
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LIST_INSERT_HEAD(&parent->p_children, p2, p_sibling);
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p2->p_exitsig = exitsig; /* signal for parent on exit */
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LIST_INSERT_AFTER(p1, p2, p_pglist);
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LIST_INSERT_HEAD(&allproc, p2, p_list);
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p2->p_trace_enabled = trace_is_enabled(p2);
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#ifdef __HAVE_SYSCALL_INTERN
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(*p2->p_emul->e_syscall_intern)(p2);
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#endif
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/*
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* Update stats now that we know the fork was successful.
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*/
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uvmexp.forks++;
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if (flags & FORK_PPWAIT)
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uvmexp.forks_ppwait++;
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if (flags & FORK_SHAREVM)
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uvmexp.forks_sharevm++;
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/*
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* Pass a pointer to the new process to the caller.
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*/
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if (rnewprocp != NULL)
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*rnewprocp = p2;
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if (ktrpoint(KTR_EMUL))
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p2->p_traceflag |= KTRFAC_TRC_EMUL;
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/*
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* Notify any interested parties about the new process.
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*/
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|
if (!SLIST_EMPTY(&p1->p_klist)) {
|
|
mutex_exit(proc_lock);
|
|
KNOTE(&p1->p_klist, NOTE_FORK | p2->p_pid);
|
|
mutex_enter(proc_lock);
|
|
}
|
|
|
|
/*
|
|
* Make child runnable, set start time, and add to run queue except
|
|
* if the parent requested the child to start in SSTOP state.
|
|
*/
|
|
tmp = (p2->p_userret != NULL ? LW_WUSERRET : 0);
|
|
mutex_enter(p2->p_lock);
|
|
|
|
/*
|
|
* Start profiling.
|
|
*/
|
|
if ((p2->p_stflag & PST_PROFIL) != 0) {
|
|
mutex_spin_enter(&p2->p_stmutex);
|
|
startprofclock(p2);
|
|
mutex_spin_exit(&p2->p_stmutex);
|
|
}
|
|
|
|
getmicrotime(&p2->p_stats->p_start);
|
|
p2->p_acflag = AFORK;
|
|
lwp_lock(l2);
|
|
if (p2->p_sflag & PS_STOPFORK) {
|
|
p2->p_nrlwps = 0;
|
|
p2->p_stat = SSTOP;
|
|
p2->p_waited = 0;
|
|
p1->p_nstopchild++;
|
|
l2->l_stat = LSSTOP;
|
|
l2->l_flag |= tmp;
|
|
lwp_unlock(l2);
|
|
} else {
|
|
p2->p_nrlwps = 1;
|
|
p2->p_stat = SACTIVE;
|
|
l2->l_stat = LSRUN;
|
|
l2->l_flag |= tmp;
|
|
sched_enqueue(l2, false);
|
|
lwp_unlock(l2);
|
|
}
|
|
|
|
mutex_exit(p2->p_lock);
|
|
|
|
/*
|
|
* Preserve synchronization semantics of vfork. If waiting for
|
|
* child to exec or exit, set PL_PPWAIT on child, and sleep on our
|
|
* proc (in case of exit).
|
|
*/
|
|
while (p2->p_lflag & PL_PPWAIT)
|
|
cv_wait(&p1->p_waitcv, proc_lock);
|
|
|
|
mutex_exit(proc_lock);
|
|
|
|
/*
|
|
* Return child pid to parent process,
|
|
* marking us as parent via retval[1].
|
|
*/
|
|
if (retval != NULL) {
|
|
retval[0] = p2->p_pid;
|
|
retval[1] = 0;
|
|
}
|
|
|
|
return (0);
|
|
}
|